Well, I guess I'm done experimenting with the Lye... It makes a cool effect, but it's still not right and I would still have to stain it anyway.

I even found a piece of White Oak to test it on, but it only made it darker..

In the picture below, the top three pieces are on Doug Fir, and the bottom two pieces are White Oak. (The oak was sanded to 80 grit).

The bottom piece is just bare wood, and it's better than all the others imo.

The one on the left of the second row, on the Doug Fir, that was just the left side of the "Liquid Plumber" bottle. It was the gel side (the right side was thinner viscosity). It did a real good job of bleaching the rings and everything. It was an interesting effect, but still not enough... not enough to make it worth messing with.

The process that you've discovered is usually used to ebonize oak, that is, turn it black. Because the tannins that combine with the iron continue to break down in the presence of the low pH caused by the vinegar, the wood will continue to darken over time until the iron is exhausted. This is not what I would call a "weathered grey", but if it's the look you want, then it's perfect.

If, over time you discover that the wood has become too black, you can wash it with oxalic acid. Oxalic acid complexes with the iron preferentially over the tannins and so it will stop the darkening reaction and even reverse it, and if you rinse it off, it won't continue to bleach the wood, as the iron oxalate washes out so it won't darken further either.

Cheers,Tom

_________________"There is no path to peace, peace is the path."Mohandas K. Ghandi

The process that you've discovered is usually used to ebonize oak, that is, turn it black. Because the tannins that combine with the iron continue to break down in the presence of the low pH caused by the vinegar, the wood will continue to darken over time until the iron is exhausted. This is not what I would call a "weathered grey", but if it's the look you want, then it's perfect.

If, over time you discover that the wood has become too black, you can wash it with oxalic acid. Oxalic acid complexes with the iron preferentially over the tannins and so it will stop the darkening reaction and even reverse it, and if you rinse it off, it won't continue to bleach the wood, as the iron oxalate washes out so it won't darken further either.

Cheers,Tom

Thanks again Tom,

I don't quite understand the underlined part above, but I do understand your overall point.

I was wondering about how to neutralize the vinegar solution, and you answered it before I even asked. Right on.

The 50/50 sample in my earlier post has already turned a little bit darker. I rinsed it well yesterday, with water, but I guess that's not enough to completely neutralize it.

The "weathered grey" color that I liked best is the lower half of the "Vinegar/Rust" sample... But that's hard to control because the wood reacts to the potion differently, depending which part of the stick it's on.

The tannins in the wood react with the iron to form a ferric gallate (tannin) compound. The oxalic acid also reacts with the iron, preferentially over the tannins, so the ferric gallate compound is destroyed to instead form a ferric oxalate compound that can be washed out.

The oxalic acid doesn't neutralize the acetic acid in the vinegar, it out competes the tannin for the iron.

Cheers,Tom

Ps. Heartwood contains more tannins than sapwood, so heartwood will pigment darker than sapwood.

_________________"There is no path to peace, peace is the path."Mohandas K. Ghandi

I was just reading one of the wood magazines last night and saw an ad for Varathane Weathered Wood Accelerator. Sounds like it is just what you are looking for and appears to be easier to control as far as color goes. Main ingredient is Ferrous Sulfate Heptahydrate, which appears to contain iron (like the steel wool and vinegar solution) and some other chemicals to react with the tannins. Water soluble and soap & water clean up. Here's the link for the MSDS sheet. http://www.rustoleum.com/~/media/Digita ... r_TDS.ashx

I was just reading one of the wood magazines last night and saw an ad for Varathane Weathered Wood Accelerator. Sounds like it is just what you are looking for and appears to be easier to control as far as color goes. Main ingredient is Ferrous Sulfate Heptahydrate, which appears to contain iron (like the steel wool and vinegar solution) and some other chemicals to react with the tannins. Water soluble and soap & water clean up. Here's the link for the MSDS sheet. http://www.rustoleum.com/~/media/Digita ... r_TDS.ashx

No experience with it and as they say, your mileage may vary

HTH

Thanks John. That stuff was mentioned early in this thread too, but I still haven't seen it at any local stores...

I think I'm gonna just use stain on this project... it's much easier to control.

The vinegar and steel wool solution worked really good, but it's hard to control the effect. Different parts of the same board will yield dramatically different results, as you can see in my previous samples. I like the pale grey parts, but if I get dark streaks in places, it will be a disaster for this project. ...The other reason I don't want to use it is because the effect continues for days (as Tom described), and so, what might originally look perfect will wind up getting too dark after a while.

The vinegar and rust solution is really cool though! I intend to do something with it one of these days, but not this time. I think I would have to treat a whole board before even cutting it, and then mill it accordingly to take advantage of the effect. There would be a lot of odd shaped scraps at the end.

That vinegar/rust solution makes an awesome effect on old Douglass Fir too. At first, it turned to a dark brown almost immediately. The next day, the color turned into a very dark grey, almost black... I think I could probably "ebonize" the Doug Fir with it pretty easily. (On the White Oak, the dark parts were more like a purple color).

The tannins in the wood react with the iron to form a ferric gallate (tannin) compound. The oxalic acid also reacts with the iron, preferentially over the tannins, so the ferric gallate compound is destroyed to instead form a ferric oxalate compound that can be washed out.

The oxalic acid doesn't neutralize the acetic acid in the vinegar, it out competes the tannin for the iron.

Cheers,Tom

Ps. Heartwood contains more tannins than sapwood, so heartwood will pigment darker than sapwood.

Hey Tom, thanks again man... I appreciate you teaching me about the science of how this all works, and I think I'm getting it for the most part.

I have just a few more questions for you (for now)....

I want to make a bigger batch of that Vinegar/steel wool solution, (super strong), and just keep it on hand for a long time. What would you suggest?

I'm thinking about getting a quart of white vinegar (in a glass bottle) and packing "a loose handful" of steel wool in there... put the cap back on, and let it sit for months... Would that be safe? Should I take the steel wool out after a while? Does it create any gasses? Should I leave the cap loose so it can vent?

I would recommend a dilute vinegar solution. The idea is to dissolve the iron and not break down the tannins so much. I use a wide mouth canning jar and line the lid with plastic to slow the rusting of the lid. Steel wool works well, but I wash it with dish soap first to remove the oil left from manufacturing. Off gassing can occur but I haven't found any problem with it.

One last thing, when the steel wool has been consumed, or the reaction appears to have stopped, filter the solution through a coffee filter, or at least a paint strainer to remove the particulates.

Good luck,Tom

_________________"There is no path to peace, peace is the path."Mohandas K. Ghandi

The tannins in the wood react with the iron to form a ferric gallate (tannin) compound. The oxalic acid also reacts with the iron, preferentially over the tannins, so the ferric gallate compound is destroyed to instead form a ferric oxalate compound that can be washed out.

The oxalic acid doesn't neutralize the acetic acid in the vinegar, it out competes the tannin for the iron.

Cheers,Tom

Ps. Heartwood contains more tannins than sapwood, so heartwood will pigment darker than sapwood.

Hey Tom, I have another question for you (or anyone else too)... How do use use the oxalic acid to absorb the vinegar?

I have "Barkeepers Friend" on hand, will that work? Or should I get pure oxalic acid?

After trying the vinegar/rust solution on Ash instead of Oak, I decided to go back to "plan A"... I'll post some pics later, but I got really good results on Ash... It's very even, and it's a nice "pure" grey.. There's no real color at all, it's just a nice pale grey.

I wound up getting Ash plywood for the cabinet, and I love the way it reacts to the potion. It's waaaaay better than the stain...

After seeing that, I went and got some solid ash for all the nosing too, and the potion works even better on a solid piece

The plywood had a little bit of variation in the color, but it was subtle and it looked natural. The solid stick took the color a little darker, but it's very even and very close to the same shade... I think I should be able to control that with the oxalic acid, but a little bit of variation will be fine as long as it's not too drastic.

The color on plywood is a little lighter... and it kinda, almost, sort of, has a greenish hue to it. But I still like it much better than the stain color... And the other thing I like, is the way it really brings out the grain, instead of hiding it..

This was the "back" side of the plywood, so the seams left glue lines.

On the left side (with the spots), I brushed it on... But then there was a little passing shower, and the mist made the spots.

On the right side, I used a slightly damp rag and just rubbed it into the rest of the board. It was a "dry rub" and it was dry almost immediately.

The brown spot on the right side is where I sanded the glue line and re-applied the potion. ...the pic was taken while that part was still wet... Now that it's dry, that spot still looks like a stain, but it's not as brown as it was, and the glue line is gone.

There's no turning back now... Plan A is back... just a few more details to sort out at this point

I would suggest any available oxalic acid wood bleach product. I use Daly's because they are a local company for me. I would also dilute by about half, or more, to start slowly. Remember, a day in the sun will give you a whitish grey when you're finished.

Good luck,Tom

_________________"There is no path to peace, peace is the path."Mohandas K. Ghandi

I would suggest any available oxalic acid wood bleach product. I use Daly's because they are a local company for me. I would also dilute by about half, or more, to start slowly. Remember, a day in the sun will give you a whitish grey when you're finished.

Good luck,Tom

Sorry for the delayed response Tom, but I did get some straight Oxalic acid, and it was amazing how easy it was to wash the grey right back off! It didn't even require any elbow grease! It was like a hot knife through butter...

But for the sake of ending this thread, here's how it all worked out...

The grey color that I liked so much, came out more greenish on the "A" side of the plywood.. The "B" side came out nicely grey.

I didn't let it sit in the sun very long, for whatever that's worth...

The solid Ash nosing, and the back of the plywood, had a nice faded grey color... but the "A" side of the ply came out with a greenish tint....

So I wound putting grey stain on on top of it, and it worked out real good... It doesn't exactly look "old", and it doesn't even come close to matching the old teak bench, but the color is good. Three coats of satin poly to finish it off..

Pics don't tell the story so good, so I shot a vid to catch the different lighting effects... In real life, the grain is much more visible...

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